Alcohol abuse can have devastating consequences to individuals and society as a whole. Since the mechanisms of ethanol reinforcement are not clear, it is difficult to provide our society with good quality therapy and preventative programs. The mesolimbic dopaminergic pathway, which contains neurons from the ventral tegmental area to the nucleus accumbens, plays a role in the reinforcing properties of ethanol. Understanding the mechanisms of dopamine in the nucleus accumbens and alcohol can help gain knowledge about alcohol abuse and aid in the enhancement of treatment, diagnostics, and preventive care. The nucleus accumbens is divided into the core and shell and dopamine may play different roles in these subregions. Unfortunately, operant ethanol self-administration studies have failed to study these subregions separately. There are two aims in this proposal. First, we will determine the effect of the sensory stimuli of ethanol on dopamine in the core and shell of the nucleus accumbens during operant self-administration. We propose that the taste and smell of ethanol are cues that promote the dopamine response in the nucleus accumbens during ethanol self-administration, particularly in the core subregion. Identifying strong cues that might trigger ethanol self-administration or craving could be important in the search for better preventative care. The second aim will be to determine the effect that the first two days of ethanol self-administration have on dopamine in the core. We predict that the self-administration of 10S10E will cause an increase in dopamine in the core during the second day of operant self-administration. For both aims, Long Evans Rats will be used and microdialysis will be done to test our hypotheses. These experiments will help us further understand the role that dopamine plays in the reinforcing effects of ethanol during operant selfadministration and if the nucleus accumbens shell and core have different functions. The results from these studies can aid in the search for better treatments and preventative programs for our society.